The teen old authorities that 37-year-old Paul Gregg Jr. began yelling at the teen's mother and threatening her when they returned home that night. He said he was worried that Gregg might hurt her, so he retrieved a 12-gauge shotgun from his room. When Gregg went to the master bedroom, where several guns were kept, authorities say the teen shot Gregg in the back, killing him. The teen left the home, and his mother called 911.